Clostridium botulinum is
- bacilli , gram +ve, anarobic
- foodborne bc of improper storing of food in cans w low 02 level
- severe food poisoning aka botulism produced most potent neurotoxin: botulium toxin
- leads to respiratory paralysis
- used to treat muscle spams and cosmetic botox
Bacillus anthracis
- gram +ve
- leads to anthrax infection via skin , septicaemic infection
- forms in livestock and can infect humans
- inhalation or ingesting the spores
- inhaling is the most dangerous ( 90% mortality )
- Prevention - slaughter and burning.
anaerobic, endospores; tetanus or lockjaw due to neurotoxin; convulsive contractions in voluntary muscles; morbidity 50%
gram +ve Clostridium tetani
Staphylococcus aureus
gram +ve
Commonly found on skin and typically will not cause any health issues. However some strains can be highly pathogenic. Emergence of antibiotic-resisistant
S. aureus now a major health concern worldwide
– Common cause of sore throat (strep-throat) but can also cause severe infections including meningitis, pneumonia and necrotizing fasciitis
Streptococcus pyogenes
Vibrio cholerae
- gram -ve highly motile bc of flagella
- bacilli
- contaminated water leads to cholera toxin
- colonises the intestine and increases water secretion which leads to dehydration and severe diarrhoea
- treated by: oral rehydration therapy
Legionella pneumophila
- gram -ve , bacilli
-Legionnaires’ disease - found in contaminated water in AC, shower, and water tanks
- spread when water is aeorolized leading to inhalation of bacteria
- affects: older and immunocompromised ppl
E - coli
- gram -ve lives in gut
- bacilli
- different strains and most are harmless
- severe food poisoning, gasteroenteritis, diarrhea
- can be caused by: urinary tract infections
- affects: children and elderly
the two types of salmonella ( bacilli )
1-Salmonella enterica – Foodborne pathogen, spreads improperly stored or cooked food especially meat, eggs and dairy. Common form of food poisoning, leads to diarrhea, fever, vomiting, and abdominal cramps. Usually mild but can cause severe complications in elderly, children or immune-compromised
2-Salmonella typhi – Subset of salmonella enterica. Spread by contaminated food or water, most common in developing regions with poor sanitation. Causes typhoid fever - skin rash, fever, weakness, abdominal pain and vomiting. Vaccination, sanitation and antibiotics have reduced mortality rate from 20% to less than 1%
the simplest cell known near large virus size
-mycoplasma
-w no cell wall, varies in shape, resistance to many common antibiotics
-respiratory and urogenital tracts.
-Causes a mild type of bacterial pneumonia (approx. 20% of all pneumonia cases).
* Parasitic organism – depends on attachment to host cells for replication.
Bacteria - Rickettsiae
Obligate intracellular parasites of arthropods and mammals, must be grown on living cells
* Usually spread to humans through arthropod vectors, including ticks, fleas and lice.
the 2 types of rickettsia
1-Rickettsia prowazekii - causes classical typhus fever, the vector is the human louse; presents as
an acute fever with 10-20% morbidity. due to outbreaks in war and overcrowded prison . Can be treated with antibiotics and prevented using insecticides to decontaminate living
spaces and clothes during outbreaks, killing the lice that spread the disease
2- Rickettsia rickettsi - causes Rocky Mountain spotted fever
* Leads to tash and fever
* Spread by tick bites
* Severe cases can lead to partial paralysis of the lower extremities or gangrene requiring amputation
Chlamydia trachomatis
- Gram negative, obligate intracellular parasitic bacteria.
-Sexually transmitted disease infecting both male and female genital tracts. Can remain symptomless for long periods of time (approx. 50% of cases) - symptoms include burning pain within the genitals and inflammation and can eventually lead to infertility.
ecause it is often symptomless, regular STI screening is recommended for anyone sexually active.
-Can also infect the eyes – commonly passed from mother to child during birth. Can also be spread by flies, by direct contact or by contamination of personal items such as towels
repeated infections of the conjunctiva leads to scarring which causes the eyelashes to turn inwards is called
Trachoma from chlamydia, scraping against the eyeballs every time a patient banks leads to loss of vision, its most common cause of preventable vision loss worldwide.
mechanisms of antibiotic actions
1- Inhibition of cell wall synthesis ( Does not kill the pathogen directly but results in cell lysis due to internal osmotic pressure e.g., Penicillins, Vancomycin)
2-Inhibition of cell membrane function
( eg., Polymyxins, Nystatin;)
3- Inhibition of protein synthesis (Chloramphenicol,Tetracyclines;)
4- Inhibition of nucleic acid synthesis
( Rifampin, Sulphonamides.)
misuse of antibiotic mat lead to:
1- hypersensitivity causing rash and/or fever.2- drug resistance
3- direct drug toxity as allergic reactions, renal damage, auditory nerve damage
4- masking of serious infections without eradication.
5- changes of normal flora of the body resulting from ‘superinfection’
the misuse of antibiotics can include:
- using it when not needed as viral infections
- patient failing to complete the treatment course
- using it without medical recommendations
( misusing leads to more resistant bacteria )
